--- ccmain/equationdetect.cpp
+++ ccmain/equationdetect.cpp
@@ -162,6 +162,22 @@
   return 0;
 }
 
+#if defined(__UCLIBC__) && __UCLIBC_MAJOR__ == 0 && __UCLIBC_MINOR__ == 9 && __UCLIBC_SUBLEVEL__ <= 29
+#define NO_FMAX_IN_UCLIBC
+#endif
+
+#if defined(NO_FMAX_IN_UCLIBC)
+static double _fmax_(double x, double y) {
+  if (isnan(x))
+    return x;
+  if (isnan(y))
+    return y;
+  return x > y ? x : y;
+}
+#else
+#define _fmax_ fmax
+#endif
+
 void EquationDetect::IdentifySpecialText(
     BLOBNBOX *blobnbox, const int height_th) {
   ASSERT_HOST(blobnbox != NULL);
@@ -214,7 +230,7 @@
   BlobSpecialTextType type = BSTT_NONE;
 
   // Classification.
-  if (fmax(lang_score, equ_score) < kConfScoreTh) {
+  if (_fmax_(lang_score, equ_score) < kConfScoreTh) {
     // If both score are very small, then mark it as unclear.
     type = BSTT_UNCLEAR;
   } else if (diff > kConfDiffTh && equ_score > lang_score) {